Polymer composition containing a fluorochemical oligomer

ABSTRACT

The present invention provides a polymer composition comprising a fluorochemical oligomeric compound and a thermoplastic or thermoset polymer. The polymer composition is useful in preparing shaped articles such as fibers and films which have desirable oil- and water repellency properties.

This invention relates to fluorochemical compounds having oligomericportions that contain pendent fluoroaliphatic and fluorine-freealiphatic groups. This invention also relates to polymer compositionscomprising the fluorochemical composition and shaped articles made fromthe thermoplastic composition.

The utility of organofluorine compounds as surface-active agents (i.e.,surfactants) and surface-treating agents is due in large part to theextremely low free-surface energy of a C₆-C₁₂ fluorocarbon group,according to H. C. Fielding, “Organofluorine Compounds and TheirApplications,” R. E. Banks, Ed., Society of Chemical Industry at p. 214(1979). Generally, the organofluorine substances described above arethose which have carbon-bonded fluorine in the form of a monovalentfluoroaliphatic radical such as a perfluoroalkyl group, typically—C_(n)F_(2n+1), where n is at least 3, the terminal part of which groupis trifluoromethyl, —CF₃.

International Published Application WO 98/51723 (Allewaert et al.)discloses fluorochemical oligomer having the formula M^(f)_(m)M_(n)—Q¹—T¹, wherein M^(f) _(m)M_(n)represents fluorochemicaloligomer comprising m units derived from fluorinated monomer and n unitsderived from fluorine-free monomer, m is from about 2 to 40, n is from 0to 20, T¹is —OH or —NH₂, and Q¹—T¹ together represent the organicresidue obtained by removing a hydrogen atom from a chain transfer agentthat is functionalized with T¹.

European Publication EP 0670358 describes polymeric surfactants having afluorocarbon segment and a hydrocarbon segment in the molecule, whichcan be made by co-polymerizing a polyfluoroalkyl group-containing(meth)acrylate with a long chain (meth)acrylic alkyl ester having atleast 8 carbon atoms. The polymeric surfactants are useful for makingfluorine-containing-oil-in-hydrocarbon-oil type emulsions.

J. Polymer Science, Part A 1988, 26, 2991 (Chujo et al.) describes adi-carboxyl terminated macromonomer prepared by the free radicalco-polymerization of a perfluoroalkylethyl acrylate and methylmethacrylate in the presence of thiomalic acid. Also described is thereaction of such macromonomers with organic dicarboxylic acids andorganic diamines in the presence of an appropriate catalyst to afford acopolymer wherein the macromonomer is grafted onto a polyamide chain.

Several patents have taught that the addition of certain fluorochemicalsto thermoplastic imparts oil and stain repellency to thermoplasticarticles such as fibers. For example, U.S. Pat. No. 5,025,052 (Crater etal.) describes the use of fluoroaliphatic radical-containing2-oxazolidinone compounds having a monovalent fluoroaliphatic radicalbonded to the 5-position thereof with an organic linking group. Thecompounds are said to be useful in the surface treatment of fibrousmaterials, such as textiles and are also useful in preparing fibers,films and molded articles by melt-extrusion or injection molding. U.S.Pat. No. 5,380,778 (Buckanin) describes the use of fluorochemicalaminoalcohols in thermoplastic compositions which can be melted andshaped, for example by extrusion or molding, to provide fibers and filmshaving desirable oil- and water-repellency properties. U.S. Pat. No.5,451,622 (Boardman et al.) describes shaped articles, such as fibersand films, made by melt extruding mixtures of fluorochemical piperazinecompounds and a thermoplastic polymer. U.S. Pat. No. 5,898,046 describesrepellent compositions formed by the mixture of a thermoplastic polymerand a fluorocarbon/aliphatic hydrocarbon monoester, wherein thealiphatic hydrocarbon portion can have from about 12 to about 76 carbonatoms. International Published Application WO 97/22576 (Raiford et al.)describes fluorochemical diesters added to thermoplastic polymer meltswhich impart repellency of low surface tension fluids to the resultantfiber, fabric, nonwoven, film or molded article. International PublishedApplication WO 99/05345 (Gasper et al.) discloses a hydrophobic andoleophobic fiber comprising synthetic organic polymer and a compoundwhich is a fluorochemical ester or amide derived from a dimer or trimeracid. U.S. Pat. No. 5,411,576 (Jones et al.) describes an oily mistresistant electret filter media comprising melt-blown electretmicrofibers and a melt-processible fluorochemical having a melting pointof at least about 25° C. and a molecular weight of about 500 to 2500,the fluorochemical being a fluorochemical piperazine, oxazolidinone orperfluorinated alkane having from 15 to 50 carbon atoms. U.S. Pat. No.5,300,587 (Macia et al.) describes oil-repellent polymeric compositionsmade by blending a perfluoropolyether and a thermoplastic polymer. U.S.Pat. No. 5,336,717 (Rolando et al.) discloses fluorochemical graftcopolymers derived from reacting monomers having terminal olefinic bondswith fluorochemical olefins having fluoroaliphatic groups andpolymerizable double bonds.

International Published Application No. WO 98/15598 (Yamaguchi et al.)describes water- and oil-repellent resin compositions useful, e.g., forkitchenware and bathroom utensils, comprising thermoplastic orthermosetting resin and perfluoroalkylated polymer, such compositionsexhibiting superior anti-fouling and mouldability. The perfluoroalkylpolymer can be a copolymer of a 5 to 18 carbon perfluoroalkylgroup-containing (meth)acrylic ester and a hydrophilic group-bearing(meth)acrylic ester, with an optional copolymerizable comonomer whichcan be a C₁-C₂₅ (meth)acrylic acid alkyl ester, preferably a C₈-C₂₂alkyl ester.

While these fluorochemical melt additives can in some circumstancesimpart satisfactory hydrophobicity and/or oleophobicity to thermoplasticresins they typically suffer from poor thermal stability above 300° C.,a melt processing temperature often encountered in the industry, andthey can also be prohibitively expensive, lending limitations to theircommercial utility.

For many years nonwoven fibrous filter webs have been made frompolypropylene using melt-blowing apparatus of the type described inReport No. 4364 of the Naval Research Laboratories, published May 25,1954, entitled “Manufacture of Super Fine Organic Fibers” by Van Wenteet al. Such melt-blown microfiber webs continue to be in widespread usefor filtering particulate contaminants, e.g., as face masks and as waterfilters, and for other purposes, e.g., to remove oil from water.

Fibrous filters for removing particulate contaminants from the air arealso made from fibrillated polypropylene films. Electret filtrationenhancement can be provided by electrostatically charging the filmbefore it is fibrillated. Common polymers such as polyesters,polycarbonates, etc. can be treated to produce highly charged electretsbut these charges are usually short-lived especially under humidconditions. The electret structures may be films or sheets which findapplications as the electrostatic element in electro-acoustic devicessuch as microphones, headphones and speakers and in dust particlecontrol, high voltage electrostatic generators, electrostatic recordersand other applications.

SUMMARY OF THE INVENTION

This invention provides a polymer composition comprising a polymer andat least one fluorochemical oligomer comprising:

(i) an oligomeric portion having both fluoroaliphatic and fluorine-freealiphatic pendent groups;

(ii) an aliphatic moiety; and

(iii) a linking group which links the oligomeric portion to thealiphatic moiety; wherein the ratio of fluoroaliphatic pendent groups tofluorine-free aliphatic pendent groups is greater than or equal to 4.

A polymer composition of this invention can be melted or shaped, forexample by extrusion or molding, to produce shaped articles, such asfibers, films and molded articles whose surfaces exhibit excellent oil-and water repellency. The repellent polymer composition is especiallyuseful in the preparation of nonwoven fabrics used in medical gowns anddrapes, where repellency to bodily fluids is mandated. Films made fromrepellent polymer compositions of this invention are useful, forexample, for moisture and/or grease-resistant packaging, release liners,and multilayer constructions.

In another aspect, the present invention provides oily mist resistantelectret filter media comprising polypropylene electret fibers made fromrepellent polymer compositions of this invention, wherein thefluorinated compound has a melting temperature of at least 25° C.Preferably the fibers may be in the form of meltblown microfibers.

In another aspect, the present invention provides a method for filteringparticulate material from air containing oily aerosol particlescomprising passing said air through electret filter media made fromrepellent polymer compositions of this invention. The electret filtermedia of the present invention have improved electret filtrationenhancement and sustain that enhancement upon exposure to oily aerosols.Furthermore, the electret filter media of the present invention maintainfunctional filtration enhancing charge levels under accelerated agingconditions.

Fibrous polypropylene electret filters that are currently available,some made from melt-blown polypropylene microfibers and others fromfibrillated polypropylene film, can show thermally stable electretfiltration enhancement. Unfortunately, fibrous electret filters made ofpolypropylene, whether melt-blown microfibers or fibrillated film, tendto lose their electret enhanced filtration efficiency faster thandesired for some purposes when exposed to oily aerosols. There is a needto improve the long-term efficiency of air filters in the presence ofaerosol oils, especially in respirators.

The novel fibrous electret filter media of the present invention areespecially useful as an air filter element of a respirator such as aface mask or for such purposes as heating, ventilation, andair-conditioning. In respirator uses, the novel electret filter mediamay be in the form of molded or folded half-face masks, replaceablecartridges or canisters, or prefilters. In such uses, an air filterelement of the invention is surprisingly effective for removing oilyaerosols such as are present in cigarette smoke or in fumes fromcombustion engines. When used as an air filter media, such as in arespirator, the electret filter media has surprisingly better filtrationperformance than does a comparable electret filter media made of 100%polypropylene fibers.

DETAILED DESCRIPTION

This invention provides fluorochemical compositions comprising athermoplastic or thermoset polymer and at least one fluorochemicaloligomeric compound of Formulas I or II:

[(A)_(m)—L]_(n)R  I

(A)_(m)[L—R]_(n)  II

wherein

m is 1 or 2;

n is 1 to 4 inclusive;

each L independently comprises a linking group;

each R is a saturated or unsaturated aliphatic moiety; and

each A is a fluorochemical oligomeric portion of Formula III:

wherein

the sum of a+b is a number such that A is oligomeric and comprises aplurality of pendent R_(f) and R_(h) groups in ratios (a:b) of ≧4;

R₁ is hydrogen, halogen, or straight chain or branched chain alkylcontaining 1 to about 4 carbon atoms;

each R₂ is independently hydrogen or straight chain or branched chainalkyl containing 1 to about 4 carbon atoms;

Q and Q′ are each independently a covalent bond or an organic linkinggroup, R_(f) is a fluoroaliphatic group, such as —(CF₂)₇CF₃, thatcomprises a fully fluorinated terminal group;

R_(h) is a fluorine-free aliphatic group; and

X is a hydrogen atom or a group derived from a free radical initiator(e.g. t-butoxy.

Preferably, with reference to Formulas I and II, both m and n are one toproduce a fluorinated compound of Formula IV:

With reference to Formulas III and IV, it will be understood that theoligomer may have a random distribution of fluorinated and fluorine-freesegments, or a sequential arrangement where the oligomer comprises“blocks” of fluorinated and fluorine-free segments. Further it will beunderstood that the relative position of the units derived fromfluorinated monomers and fluorine-free monomers may vary with respect tothe X and S moieties. In essence the following structures are bothwithin the scope of the invention:

As described above and further illustrated in Formulas I-IV, afluorochemical composition of the invention comprises a fluorinatedcompound that generally has three principal portions: a fluorochemicaloligomeric portion “A” having pendent fluorinated and fluorine freeportions, a non-polymeric linking group “L”, and an aliphatic moiety“R”. The oligomeric portion and the organic moiety are linked togetherby linking group L. The linking group may be a covalent bond, may resultfrom a condensation reaction between a nucleophile, such as an alcohol,an amine, or a thiol, and an electrophile such as a carboxylic acid,ester, acyl halide, sulfonate ester, sulfonyl halide, cyanate,isocyanate, or may result from a nucleophilic displacement reactionbetween a nucleophile, such as previously described, and a moietybearing a leaving group, such as the reaction between an alcohol (oralkoxide) and an alkyl halide (where the halogen atom of the alkylhalide serves as a leaving group).

Examples of suitable linking groups L include a covalent bond, straightchain, branched chain, or cyclic alkylene, arylene, aralkylene, oxy,oxo, hydroxy, thio, sulfonyl, sulfoxy, amino, imino, sulfonamido,carboxamido, carbonyloxy, urethanylene, urylene, and combinationsthereof such as sulfonamidoalkylene.

A salient component of the oligomeric portion is the fluoroaliphaticgroup, designated herein as R_(f). The fluorinated compound of theinvention contains a plurality of pendent R_(f) groups (e.g., from 4 toabout 10) proximal to one another and preferably contains from about 5percent to about 80 percent, more preferably from about 10 percent toabout 65 percent, and most preferably about 12 percent to about 60percent fluorine by weight, based on the total weight of the compound,the loci of the fluorine being essentially in the R_(f) groups. EachR_(f) is a stable, inert, non-polar, preferably saturated, monovalentmoiety which is both oleophobic and hydrophobic. R_(f) preferablycontains at least about 3 carbon atoms, more preferably 3 to about 20carbon atoms, and most preferably about 4 to about 14 carbon atoms.R_(f) can contain straight chain, branched chain, or cyclic fluorinatedalkylene groups or combinations thereof or combinations thereof withstraight chain, branched chain, or cyclic alkylene groups. R_(f) ispreferably free of polymerizable olefinic unsaturation and canoptionally contain catenary heteroatoms such as divalent oxygen, ortrivalent nitrogen. It is preferred that R_(f) contain about ⁴⁰% toabout 78% fluorine by weight, more preferably about 50% to about 78%fluorine by weight. The terminal portion of the R_(f) group contains afully fluorinated terminal group. This terminal group preferablycontains at least 7 fluorine atoms, e.g., CF₃CF₂CF₂—, (CF₃)₂CF—, or thelike. Perfluorinated aliphatic groups (i.e., those of the formulaF_(o)F_(2o+1), where o is 4 to 14 are the most preferred embodiments ofR_(f)).

The fluorine-free aliphatic moiety, designated R_(h) in compounds ofFormulas I-IV is a monovalent, linear or branched chain, saturated orunsaturated, cyclic or acyclic (or any combination thereof)fluorine-free aliphatic group having from 1 to 75 carbon atoms. Althoughnot preferred, R_(h) may contain aromatic rings. R_(h) may containcaternary oxygen atoms. The range of structures contemplated for theorganic moiety R_(h) will be better understood with reference to thecompounds suitable for use in steps of the Reaction Schemes described indetail below. Preferably R_(h) is a linear, monovalent alkyl group ofthe structure —C_(n)H_(2n+1), where n is 1 to 75, preferably 12 to 75,and most preferably 18 to 60. Where more than one R_(h) group ispresent, such as in Formula II, or when n is greater than one in FormulaI, the sum of the carbon atoms in the R_(h) groups is preferably 100carbon atoms or fewer.

The organic aliphatic moiety, designated R in compounds of Formulas I-IVis a mono-, di-, tri- or tetravalent, linear or branched chain,saturated or unsaturated, cyclic or acyclic (or any combination thereof)organic aliphatic group having from 1 to 75 carbon atoms. R_(h) maycontain caternary oxygen atoms. Although not preferred, R may containaromatic rings and may be fluorinated (i.e. R=R_(f)). The valency isequivalent to the value of n in Formula I and is equal to 1 in FormulaII. The range of structures contemplated for the organic moiety R willbe better understood with reference to the compounds suitable for use insteps of the Reaction Schemes described in detail below. Preferably R isa linear, monovalent alkyl group of the structure —C_(n)H_(2n+1), wheren is 1 to 75, preferably 12 to 75, and most preferably 18 to 60. Wheremore than one R group is present, such as in Formula II, or when n isgreater than one in Formula I, the sum of the carbon atoms in the Rgroups is preferably 100 carbon atoms or fewer.

It is most preferred that at least one of the R_(h) or R groups have ≧22carbon atoms. Such compounds are novel and have enhanced oil repellencyand DOP performance (when used as a melt additive in the preparation ofblown microfibers for filtration).

The aliphatic backbone of the fluorochemical oligomeric portioncomprises a sufficient number of polymerized units to render the portionoligomeric. The aliphatic backbone preferably comprises from 5 to about10 polymerized units (“a” and “b” in Formula IV) derived fromfluorinated and fluorine-free monomers (i.e., monomers containing afluorinated aliphatic group R_(f) and a fluorine-free aliphatic groupR_(h) as defined above), it is more preferred that the aliphaticbackbone comprise from 5 to about 8, most preferably about 5,polymerized units.

The fluorochemical compositions of the invention generally comprisemixtures of alkylated fluorochemical oligomeric compounds. Accordingly,compounds are sometimes referred to herein as having non-integralnumbers of particular substituents (e.g., “a=4.7”) . In such cases thenumber indicates an average and is not intended to denote fractionalincorporation of a substituent. The terms “oligomer” or “oligomeric”when used herein designate compounds containing a plurality ofpolymerized units, but fewer than that number of polymerized unitspresent in a polymer (e.g., chains of 5 to about 20 polymerized unitsare to be considered “oligomeric”) .

The fluoroaliphatic group R_(f) and the fluorine-free aliphatic groupare each linked to the organic portion (i.e. the oligomeric backbone orthe unsaturated portion of the monomer) by a linking groups designatedas Q and Q′ respectively in the formulas used herein. Q and Q′ areindependently linking groups that may be a covalent bond, divalentalkylene, or a group that can result from the condensation reaction of anucleophile such as an alcohol, an amine, or a thiol with andelectrophile, such as an ester, acid halide, isocyanate, sulfonylhalide, sulfonyl ester, or may result from a displacement reactionbetween a nucleophile and leaving group. Each Q and Q′ is areindependently chosen, preferably contains from 1 to about 20 carbonatoms and can optionally contain catenary oxygen, nitrogen, sulfur, orsilicon-containing groups or a combination thereof Q and Q′ ispreferably free of functional groups that substantially interfere withfree-radical oligomerization (e.g., polymerizable olefinic double bonds,thiols, easily abstracted hydrogen atoms such as cumyl hydrogens, andother such functionality known to those skilled in the art). Examples ofsuitable linking groups Q and Q′ include straight chain, branched chain,or cyclic alkylene, arylene, aralkylene; oxy, oxo, hydroxy, thio,sulfonyl, sulfoxy, amino, imino, sulfonamido, carboxamido, carbonyloxy,urethanylene, urylene, and combinations thereof such assulfonamidoalkylene. Preferably linking group Q is a covalent bond or asulfonamidoalkylene group. Preferably linking group Q′ is a covalentbond.

Suitable linking groups Q and Q′ include the following structures inaddition to a covalent bond. For the purposes of this list, each k isindependently an integer from 0 to about 20, R₁′ is hydrogen, phenyl, oralkyl of 1 to about 4 carbon atoms, and R₂′ is alkyl of 1 to about 20carbon atoms. Each structure is non-directional, i.e. —(CH₂)_(k)C(O)O—is equivalent to —O(O)C(CH₂)_(k)—.

—SO₂NR₁′(CH₂)_(k)O(O)C— —CONR₁′(CH₂)_(k)O(O)C— —(CH₂)_(k)O(O)C——CH₂CH(OR₂′)CH₂O(O)C— —(CH₂)_(k)C(O)O— —(CH₂)_(k)SC(O)——(CH₂)_(k)O(CH₂)_(k)O(O)C— —(CH₂)_(k)S(CH₂)_(k)O(O)C——(CH₂)_(k)SO₂(CH₂)_(k)O(O)C— —(CH₂)_(k)S(CH₂)_(k)OC(O)——(CH₂)_(k)SO₂NR₁′(CH₂)_(k)O(O)C— —(CH₂)_(k)SO₂— —SO₂NR₁′(CH₂)_(k)O——SO₂NR₁′(CH₂)_(k)— —(CH₂)_(k)O(CH₂)_(k)C(O)O——(CH₂)_(k)SO₂NR₁′(CH₂)_(k)C(O)O— —(CH₂)_(k)SO₂(CH₂)_(k)C(O)O——CONR₁′(CH₂)_(k)C(O)O— —(CH₂)_(k)S(CH₂)_(k)C(O)O— —CH₂CH(OR₂′)CH₂C(O)O——SO₂NR₁′(CH₂)_(k)C(O)O— —(CH₂)_(k)O— —(CH₂)_(k)NR₁′C(O)O——OC(O)NR′(CH₂)_(k)—

The fluorinated compounds and fluorochemical compositions of theinvention will be illustrated with reference to the embodiments shown inFormulas I-IV. In such embodiments, linking group L links thefluorochemical oligomeric portion A to the aliphatic group R. Eachlinking group L may be a covalent bond, a di- or polyvalent alkylenegroup, or a group that can result from the condensation reaction of anucleophile such as an alcohol, an amine, or a thiol with anelectrophile, such as an ester, acid halide, isocyanate, sulfonylhalide, sulfonyl ester, or may result from a displacement reactionbetween a nucleophile and leaving group. Each L is independently chosen,preferably contains from 1 to about 20 carbon atoms and can optionallycontain catenary (i.e. in-chain) oxygen, nitrogen, sulfur, orsilicon-containing groups or a combination thereof L is preferably freeof functional groups that substantially interfere with free-radicaloligomerization (e.g., polymerizable olefinic double bonds, thiols,easily abstracted hydrogen atoms such as cumyl hydrogens, and other suchdetrimental functionalities known to those skilled in the art). Examplesof suitable linking groups L include straight chain, branched chain, orcyclic alkylene, arylene, aralkylene, oxy, oxo, sulfonyl, sulfoxy,amino, imino, sulfonamido, carboxamido, carbonyloxy, urethanylene,ureylene, and combinations thereof such as sulfonamidoalkylene.Preferred L groups include a covalent bond and the following structureswherein each k is independently an integer from 0 to about 20, R₁′ ishydrogen, phenyl, or alkyl of 1 to about 4 carbon atoms, and R₂′ isalkyl of 1 to about 20 carbon atoms.

—(CH₂)_(k)O(O)C— —CH₂CH(OR₂′)CH₂C(O)O— —(CH₂)_(k)C(O)O— —(CH₂)_(k)O— and—(CH₂)_(k)O(CH₂)_(k)O(O)C— —(CH2)_(k)OCONH—

Returning now to Formulas I-IV above, R₁ is hydrogen, halogen (e.g.,fluoro, chloro, bromo), or straight chain or branched chain alkyl of 1to about 4 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, butyl,isobutyl, and the like). Each R₂ is independently hydrogen or straightchain or branched chain alkyl of I to about 4 carbon atoms.

X is a group derived from a free-radical initiator. As used herein, theterm “free-radical initiator” designates any of the conventionalcompounds such as organic azo compounds, organic peroxides (e.g., diacylperoxides, peroxyesters, dialkyl peroxides) and the like that provideinitiating radicals upon homolysis. As used herein, the term “groupderived from a free-radical initiator” designates an initiating radicalformed upon homolytic decomposition of a free-radical initiator.

Suitable groups X include non-reactive groups such as a hydrogen atom,t-butoxy (derived from di-t-butyl peroxide), and benzoyloxy (derivedfrom benzoyl peroxide), and reactive groups such as —CCH₃(CN)CH₂CH₂CO₂H(derived from azo-4-cyanoisovaleric acid), —C(CH₃)₂CN (derived fromazoisobutyronitrile), and those derived from other known functional azocompounds such as2,2′-azobis[N-(4-chlorophenyl)-2-methylpropionamidine]-dihydrochloride;2,2′-azobis[N-(4-hydroxyphenyl)-2-methylpropionamidine]dihydrochloride;2,2,-azobis[N-(4-aminophenyl)-2-methylpropionamidine]-tetrahydrochloride;2,2′-azobis[2-methyl-N-2-propenylpropionamidine]dihydrochloride;2,2′-azobis[N-(2-hydroxyethyl)-2-methylpropionamidine]-dihydrochloride;2,2′-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide];2,2′-azobis[2-(hydroxymethyl)propionitrile];2,2′-azobis[2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide];and 2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]-propionamide).Preferred groups X include those enumerated above.

The fluorochemical compounds of Formulas I, II and IV can be prepared byoligomerization of an unsaturated, fluorinated compound (V) in thepresence of a free-radical initiator and chain-transfer agent of theformula L(SH)_(m) (for m=1) according to the following Scheme:

Scheme 1

The moiety “L” corresponds to the linking group moiety L of Formula I,II and IV.

When the chain-transfer agent contains more than one sulfhydryl group,multiple oligomeric groups A may be linked through linking group L toone or more aliphatic R groups. For examples, when the chain transferagent contains two sulfhydryl groups, two oligomeric groups A may belinked to L as follows:

Scheme 2

Compounds of Formula (V) and methods for the preparation thereof areknown and disclosed, e.g., in U.S. Pat. No. 2,803,615 (Ahlbrecht et al.)and U.S. Pat. No. 2,841,573 (Ahlbrecht et al.) which disclosures areincorporated herein by reference. Examples of such compounds includegeneral classes of fluorochemical monomers such as acrylates,methacrylates, vinyl ethers, and allyl compounds containing fluorinatedsulfonamido groups, acrylates or methacrylates derived fromfluorochemical telomer alcohols, fluorochemical thiols, and the like.Preferred compounds of Formula V includes N-methylperfluorooctanesulfonamidoethyl acrylate, N-methylperfluorooctanesulfonamidoethyl methacrylate, N-ethylperfluorooctanesulfonamidoethyl acrylate, N-ethylperfluorohexylsulfonamidoethyl methacrylate, the reaction product ofisocyanatoethyl methacrylate and N-methylperfluorooctanesulfonamidoethylalcohol, 1,1-dihydroperfluorooctyl acrylate, N-methylperfluorooctanesulfonamidoethyl vinyl ether, C₈F₁₇SO₂NHCH₂CH═CH₂,C₈F₁₇SO₂NCH₃CH₂CH═CH₂, and others such perfluorocyclohexyl acrylate(c-C₆F₁₁CH₂OCOCH═CH₂), and tetrameric hexafluoropropyleneoxidedihydroacrylate.

Compounds of Formula VI may be selected from alkyl acrylate esters,vinyl acetate, styrene, alkyl vinyl ethers, alkyl methacrylate esters,acrylic acid, methacrylic acid, acrylamide, methacrylamide,acrylonitrile, methacrylonitrile, and N-vinylpyrrolidone. Alkyl acrylateester monomers useful in the invention include straight-chain, cyclic,and branched-chain isomers of alkyl esters containing C₁-₅₀ alkylgroups. Useful specific examples of alkyl acrylate esters include:methyl acrylate, ethyl acrylate, n-propyl acrylate, 2-butyl acrylate,iso-amyl acrylate, n-hexyl acrylate, heptyl acrylate, n-octyl acrylate,iso-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decylacrylate, undecyl acrylate, dodecyl acrylate, tridecyl acrylate, andtetradecyl acrylate. Due to performance considerations, preferred alkylacrylate esters (Rh groups) are those having from C₂₂-C₅₀ alkyl groupswhen the “R” groups have fewer than 22 carbon atoms. The coverse is alsotrue.

When the chain transfer agent L(SH)_(m) bears a functional group, acompound of Formula VII (Scheme 1) is further reacted with a functionalaliphatic compound to form the linking group L and incorporate the Rgroup into the compounds of Formulas I, II and IV. The nature of thefunctional groups on both the chain transfer agent and the aliphaticcompounds are chosen so that they are reactive toward one another toform the L linking group. Examples of mutually reactive pairs include anacyl group (such as a carboxylic acid, acyl halide or ester) reactingwith an alcohol or amine, an alcohol or an amine reacting with a“leaving group” such as a halide or tosylate, and an isocyanate reactingwith an alcohol or amine.

A compound of Formulas VII or VIII can be provided with functionalgroups on the L linking group (in addition to the sulfhydryl group(s))through the use of an appropriate functionalized chain-transfer agentL(SH)_(m), wherein L contains a functional group. Suitable functionalgroups for inclusion in the chain-transfer agent include hydroxy, amino,halo, epoxy, haloformyl, aziridinyl, acid groups and salts thereof,which react with an electrophile or nucleophile, or are capable offurther transformation into such groups. The use of a functionalizedchain-transfer agent allows for subsequent incorporation of the “R”group of Formulas I and II. For example, the “L” group of the chaintransfer agent may be substituted with an electrophilic ester moiety.This ester moiety will allow incorporation of a long chain “R” group byfurther reaction with an aliphatic alcohol having a nucleophilichydroxyl group. Reaction between the two moieties produces an esterlinkage, thereby linking the fluorochemical oligomeric moiety A with thealiphatic moiety R. Alternatively, for example, the L moiety may besubstituted with a hydroxyl group that may be reacted with an aliphaticester to link the fluorochemical oligomeric moiety A with the aliphaticmoiety R.

Examples of such functionalized chain transfer agents include2-mercaptoethanol, mercaptoacetic acid, 2-mercaptobenzimidazole,2-mercaptobenzoic acid, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole,3-mercapto-2-butanol, 2-mercaptosulfonic acid, 2-mercaptonicotinic acid,4-hydroxythiopheno3-mercapto-1,2-propanediol, 1-mercapto-2-propanol,2-mercaptopropionic acid, N-(2-mercaptopropionyl)glycine,3-mercaptopropyltrimethoxysilane, 2-mercaptopyridine,2-mercaptopyridine-N-oxide, 2-mercaptopyridinol, mercaptosuccinic acid,2,3-mercaptopropanesulfonic acid, 2,3-dimercaptopropanol,2,3-dimercaptosuccinic acid, cystine, cystine hydrochloride, cystineethyl ester. Preferred functionalized chain-transfer agents include2-mercaptoethanol, 3-mercapto-1,2-propanediol, 4-mercaptobutanol,11-mercaptoundecanol, mercaptoacetic acid, 3-mercaptopropionic acid,12-mercaptododecanoic acid, 2-mercaptoethylamine,1-chloro-6-mercapto-4-oxahexan-2-ol, 2,3-dimercaptosuccinic acid,2,3-dimercaptopropanol, 3-mercaptopropyltrimethoxysilane,2-chloroethanethiol, 2-amino-3-mercaptopropionic acid, and compoundssuch as the adduct of 2-mercaptoethylamine and caprolactam.

Advantageously, the R group of Formulas I, II and IV may be incorporatedby use of a non-functional chain transfer agents. Non-functionalizedchain-transfer agents are those that contain a group capable ofterminating a radical chain reaction (e.g., a sulfhydryl) but nofurther, functional groups capable of reacting with nucleophiles,electrophiles, or capable of undergoing displacement reactions. In suchcases, the aliphatic portion of L(SH)_(n) provides the aliphatic group Rof Formulas I and II. Such compounds include mono, di, and polythiolssuch as ethanethiol, propanethiol, butanethiol, hexanethiol,n-octylthiol, t-dodecylthiol, 2-mercaptoethyl ether,2-mercaptoimidazole, 2-mercaptoethylsulfide, 2-mercaptoimidazole,8-mercaptomenthone, 2,5-dimercapto-1,3,4-thiadiazole,3,4-toluenedithiol, o-, m-, and p-thiocresol, ethylcyclohexanedithiol,p-menthane-2,9-dithiol, 1,2-ethanedithiol, 2-mercaptopyrimidine, and thelike. Longer chain alkyl thiols having 12 to 75 carbon atoms arepreferred.

Whether functionalized or not, a chain transfer agent is present in anamount sufficient to control the number of polymerized monomer units inthe oligomer. The chain transfer agent is generally used in an amount ofabout 0.025 to about 0.2 equivalents, per equivalent of combinedolefinic monomers V and VI.

Also present in oligomerization process is a free-radical initiator asdefined above in connection with X. Such compounds are known to thoseskilled in the art and include persulfates, azo compounds such asazoisobutyronitrile and azo-2-cyanovaleric acid and the like,hydroperoxides such as cumene, t-butyl, and t-amyl hydroperoxide,dialkyl peroxides such as di-t-butyl and dicumyl peroxide, peroxyesterssuch as t-butyl perbenzoate and di-t-butylperoxy phthalate,diacylperoxides such as benzoyl peroxide and lauroyl peroxide.

The initiating radical formed by an initiator can be incorporated intothe fluorochemical oligomer to varying degrees depending on the type andamount of initiator used. A suitable amount of initiator depends on theparticular initiator and other reactants being used. About 0.1 percentto about 5 percent, preferably about 0.1 percent, to about 0.8 percent,and most preferably about 0.2 percent to 0.5 percent by weight of aninitiator can be used, based on the total weight of all other reactantsin the reaction.

The oligomerization reaction of Schemes 1 and 2 can be carried out inany solvent suitable for organic free-radical reactions. The reactantscan be present in the solvent at any suitable concentration, e.g., fromabout 5 percent to about 90 percent by weight based on the total weightof the reaction mixture. Examples of suitable solvents include aliphaticand alicyclic hydrocarbons (e.g., hexane, heptane, cyclohexane),aromatic solvents (e.g., benzene, toluene, xylene), ethers (e.g.,diethylether, glyme, diglyme, diisopropyl ether), esters (e.g., ethylacetate, butyl acetate), alcohols (e.g., ethanol, isopropyl alcohol),ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone),sulfoxides (e.g., dimethyl sulfoxide), amides (e.g.,N,N-dimethylformamide, N,N-dimethylacetamide), halogenated solvents suchas methylchloroform, FREON™ 113, trichloroethylene,α,α,α-trifluorotoluene, fluorinated ethers such as C₄F₉OCH₃ and thelike, and mixtures thereof.

The oligomerization can be carried out at any temperature suitable forconducting an organic free-radical reaction. Particular temperature andsolvents for use can be easily selected by those skilled in the artbased on considerations such as the solubility of reagents, thetemperature required for the use of a particular initiator, and thelike. While it is not practical to enumerate a particular temperaturesuitable for all initiators and all solvents, generally suitabletemperatures are between about 30 deg. C. and about 200 deg. C.

The present invention provides a synthetic organic polymer compositioncomprising the one or more of the fluorinated oligomers of Formulas Iand/or II and a thermoplastic or thermoset organic polymer. Theoligomers are useful as polymer melt additives to impart desirable lowsurface energy properties to the thermoplastic or thermoset polymer.

Useful polymers include both thermoplastic and thermoset polymers andinclude synthetic linear polyamides, e.g., nylon-6 and nylon-66,polyesters, e.g., polyethylene terephthalate, polyurethanes, epoxides,epoxy resins, acrylates, polystyrenes and polyolefins, e.g.,polyethylene and polypropylene. Thermoplastic polymers such aspolyolefins are preferred. The resultant articles, due to the presenceof the fluorochemical oligomer, have improved oil- and water-repellency,low surface energy and a resistance to soiling.

Shaped articles (e.g., fibers, films and molded or extruded articles) ofthis invention can be made, e.g., by blending or otherwise uniformlymixing the alkylated fluorochemical oligomer and the polymer, forexample by intimately mixing the oligomer with pelletized or powderedpolymer, and melt extruding the mixture into shaped articles such aspellets, fibers, or films by known methods. The oligomer can be mixedper se with the polymer or can be mixed with the polymer in the form ofa “masterbatch” (concentrate) of the oligomer in the polymer.Masterbatches typically contain from about 10% to about 25% by weight ofthe fluorochemical additive. Also, an organic solution of the oligomermay be mixed with the powdered or pelletized polymer, the mixture driedto remove solvent, then melted and extruded into the desired shapedarticle. Alternatively, molten oligomer (as a compound(s) ormasterbatch) can be injected into a molten polymer stream to form ablend just prior to extrusion into the desired shaped article.

When using thermoset resins, such as epoxy resins, urethanes andacrylates, the alkylated fluorochemical oligomer may be mixed with theresin and cured by application of heat. Preferably such thermoset resinsmay be processed by reactive extrusion techniques such as are taught inU.S. Pat. No. 4,619,976 (Kotnour) and U.S. Pat. No. 4,843,134 (Kotnour)the disclosures of which are herein incorporated by reference.

The thermoplastic composition containing alkylated fluorochemicaloligomeric compounds of the present invention may be used to provide oiland water repellency to fibers. The fluorochemical oligomers are meltprocessible, i.e., suffer substantially no degradation under the meltprocessing conditions used to form the fibers. The fluorochemicaloligomers preferably have a molecular weight in the range of about 1000to 10,000, more preferably in the range of about 1500 to 5000. Thefluorochemical oligomer is preferably substantially free from mobilepolar and/or ionic species, contaminants and impurities which couldincrease the electrical conductivity or otherwise interfere with theability of the fibers to accept and hold electrostatic charges.

The amount of oligomer in the composition is that amount sufficient toproduce a shaped article having a surface with the desired properties ofoil and water repellency and/or soiling resistance. Preferably, theamount of oligomer will be that amount which provides from about 100 to10,000 ppm fluorine, more preferably 200 to 5000 ppm, most preferably400 to 3000 ppm fluorine, based on the weight of the shaped article.

After melt extrusion of a fiber, film or extruded article, an annealingstep may be carried out to enhance oil and water repellency. Annealingapparently allows the fluorochemical oligomer to migrate to the surfaceof the thermoplastic polymer with a resultant increase in repellencyproperties, reduced surface activity, improved solvent resistance andimproved release properties. The fiber or film is annealed for at atemperature and for a time sufficient to increase the amount offluorochemical oligomer at the surface. Effective time and temperaturewill bear an inverse relationship to one another and a wide variety ofconditions will be suitable. Using polypropylene, for example, theannealing process can be conducted below the melt temperature at about50° to 120° C. for a period of about 30 seconds to 10 minutes. Annealingmay also be effected by contact with heated rolls, such as embossingrolls, at 50° C. to 160° C. for periods of about 1 to 30 seconds. Insome cases, the presence of moisture during annealing, e.g., by using anautoclave to anneal, can improve the effectiveness of the fluorochemicaloligomer. The annealing method may also serve to reduce the amount ofoligomer necessary by maximizing fluorine content at the surface of thepolymer.

In addition to their use in modifying the properties of fibers, thepolymer composition of the invention is also useful in preparing blownmicrofibers for non-woven fabrics having low surface energy, oil andwater repellency and/or soiling resistance. The resin, such aspolypropylene, used to form the melt blown microfibers should besubstantially free from materials such as antistatic agents which couldincrease the electrical conductivity or otherwise interfere with theability of the fibers to accept and hold electrostatic charges. When thefluorochemical compounds of the invention are used as additives to meltblown microfibers, the additive is preferably present in amounts ofabout 0.2 to 10 weight percent, more preferably from 0.5 to 5 weightpercent and most preferably 0.5 to 2 weight percent.

As used herein, the terms “fiber” and “fibrous” refer to particulatematter, generally thermoplastic resin, wherein the length to diameterratio of the particulate matter is greater than or equal to about 10.Fiber diameters may range from about 0.5 micron up to at least 1,000microns. Each fiber may have a variety of cross-sectional geometries,may be solid or hollow, and may be colored by, e.g., incorporating dyeor pigment into the polymer melt prior to extrusion.

The non-woven webs of fibers of thermoplastic olefinic polymer for usein this invention include non-woven webs manufactured by any of thecommonly known processes for producing non-woven webs. For example, thefibrous non-woven web can be made by spunbonding techniques ormelt-blowing techniques or combinations of the two. Spunbonded fibersare typically small diameter fibers which are formed by extruding moltenthermoplastic polymer as filaments from a plurality of fine, usuallycircular capillaries of a spinneret with the diameter of the extrudedfibers being rapidly reduced. Meltblown fibers are typically formed byextruding the molten thermoplastic material through a plurality of fine,usually circular, die capillaries as molten threads or filaments into ahigh velocity, usually heated gas (e.g. air) stream which attenuates thefilaments of molten thermoplastic material to reduce their diameter.Thereafter, the meltblown fibers are carried by the high velocity gasstream and are deposited on a collecting surface to form a web ofrandomly disbursed meltblown fibers. Any of the non-woven webs may bemade from a single type of fiber or two or more fibers which differ inthe type of thermoplastic olefinic polymer and/or thickness.Alternatively, sheath-core fibers can be extruded, containing differentpolymer compositions in each layer or containing the same polymercomposition in each layer but employing the more expensivefluorochemical component in the outer sheath layer.

The melt blown polypropylene microfibers useful in the present inventioncan be prepared as described in Van Wente, A., “Superfine ThermoplasticFibers,” Industrial Engineering Chemistry, vol. 48, pp. 1342-1346 (1956)and in Report No. 4364 of the Naval Research Laboratories, published May25, 1954, entitled “Manufacture of Super Fine Organic Fibers” by VanWente et al. or from microfiber webs containing particulate matter suchas those disclosed, for example, in U.S. Pat. No. 3,971,373 (Braun),U.S. Pat. No. 4,100,324 (Anderson) and U.S. Pat. No. 4,429,001 (Kolpinet al.), which patents are incorporated herein by reference. Multilayerconstructions of nonwoven fabrics enjoy wide industrial and commercialutility and include uses such as fabrics for medical gowns and drapes.The nature of the constituent layers of such multilayer constructionscan be varied according to the desired end use characteristics, and cancomprise two of more layers of melt-blown and spun-bond webs in mayuseful combinations such as described in U.S. Pat. Nos. 5,145,727 and5,149,576, both descriptions of which are incorporated herein byreference. The filtering efficiency of a melt-blown microfiber web canbe improved by a factor of two or more when the melt-blown fibers arebombarded as they issue from the orifices with electrically chargedparticles such as electrons or ions, thus making the fibrous web anelectret. Similarly, the web can be made an electret by exposure to acorona after it is collected. Melt-blown polypropylene microfibers areespecially useful, while other polymers may also be used such aspolycarbonates and polyhalocarbons that may be melt-blown and haveappropriate volume-resistivities under expected environmentalconditions.

Any of a wide variety of constructions, especially multilayerconstructions such as SMS (spunbond/meltblown/spunbond) constructions,may be made from the above-described fibers and fabrics, and suchconstructions will find utility in any application where some level ofhydrophobicity, oleophobicity (or other fluid repellency, such as tobodily fluids) is required. The fibers prepared from the syntheticorganic polymer composition of the invention may be used in woven andnonwoven medical fabrics (such as drapes, gowns and masks), industrialapparel, outdoor fabrics (such as umbrellas, awning, tents, etc),raincoats and other outdoor apparel, as well as home furnishings such astable linens and shower curtains, and in myriad other related uses.

Preferably, the filter media is annealed, i.e., heated for a sufficienttime at a sufficient temperature to cause the fluorochemical additive tobloom to the surface of the fibers. Generally, about 1 to 10 minutes atabout 140 deg. C. is sufficient although shorter times may be used athigher temperatures and longer times may be required at lowertemperatures.

Blown microfibers for fibrous electret filters of the inventiontypically have an effective fiber diameter of from about 5 to 30micrometers, preferably from about 7 to 10 micrometers, as calculatedaccording to the method set forth in Davies, C. N., “The Separation ofAirborne Dust and Particles,” Institution of Mechanical Engineers,London, Proceedings 1B, 1952.

The electret filter media of the present invention preferably has abasis weight in the range of about 10 to 500 g/m², more preferably about10 to 100 g/m². In making melt-blown microfiber webs, the basis weightcan be controlled, for example, by changing either the collector speedor the die throughput. The thickness of the filter media is preferablyabout 0.25 to 20 mm, more preferably about 0.5 to 2 mm. The electretfilter media and the polypropylene resin from which it is producedshould not be subjected to any unnecessary treatment which mightincrease its electrical conductivity, e.g., exposure to gamma rays,ultraviolet irradiation, pyrolysis, oxidation, etc.

The melt-blown microfibers or fibrillated fibers of the electret filtersof the invention can be electrostatically charged by a process describedin U.S. Pat. Nos. Re. 30,782 (van Turnhout) or Re. 31,285 (van Turnhout)or by other conventional methods for charging or polarizing electrets,e.g., by a process of U.S. Pat. No. 4,375,718 (Wadsworth et al.); U.S.Pat. No. 4,588,537 (Klasse et al.); or U.S. Pat. No. 4,592,815 (Nakao).In general, the charging process involves subjecting the material tocorona discharge or pulsed high voltage.

Films prepared from the composition of this invention can be made whichare useful, for example, for grease-resistant packaging, release linersand microporous film applications. These films can be used to makemulti-layer constructions in which one, more than one, or all layerscontain the fluorochemical oligomeric compound.

This invention is illustrated by, but is not intended to be limited to,the following examples. Unless otherwise specified, all percentagesshown in the examples and test methods, which follow, are percentages byweight.

GLOSSARY

UNILIN™ 700—polyethylene 700 alcohol (having about 50 carbon atoms),available from Baker Petrolite Corp., Tulsa, Okla.

UNILIN™ 700A—To a three necked round bottom flask equipped with amechanical stirrer and a Dean-Stark apparatus was added 200 g (0.231mol) of UNILIN™ 700, 16.7 g (0.231 mol) of acrylic acid, 2 g ofmethanesulfonic acid and 400 mL of toluene. The resulting mixture washeated to reflux for approximately 15 hours, during which time water hadcollected in the Dean-Stark apparatus. IR of the reaction product showedno —COOH and —OH peaks, indicating that the ester formation wascomplete. To the hot ester solution was slowly added 10 g of Ca(OH)₂while stirring. and then hot filtered. The resulting mixture wasfiltered hot, the toluene was removed from the filtrate by heating underreduced pressure, and the remaining wet solid was dried in a vacuumoven. Also available as X-8503™ from Baker-Petrolite, Tulsa, Okla.

UNILIN™ 425—polyethylene 460 alcohol (having about 32 carbon atoms),available from Baker Petrolite Corp.

UNILIN™ 425A—To a three necked round bottom flask equipped with amechanical stirrer and a Dean-Stark apparatus was added 150 g (0.280mol) of UNILIN™ 425, 20.2 g (0.280 mol) of acrylic acid, 1.5 g ofmethanesulfonic acid and 300 mL of toluene. The resulting mixture washeated to reflux for approximately 15 hours, during which time water hadcollected in the Dean-Stark apparatus. Infrared spectra (IR) of thereaction product showed no —COOH and —OH peaks, indicating that theester formation was complete. To the hot ester solution was slowly added10 g of Ca(OH)₂ while stirring. The resulting mixture was filtered hot,the toluene was removed from the filtrate by heating under reducedpressure, and the remaining wet solid was dried in a vacuum oven.

stearyl alcohol—C₁₈H₃₇OH, available from Aldrich Chemical Co.,Milwaukee, Wis.

behenyl alcohol—C₂₂H₄₅OH, available from Henkel Corp., Emery Group,Cincinnati, Ohio. as HENKEL 3302.

ODA—octadecyl acrylate, C₁₈H₃₇OC(O)CH═CH₂, available from AldrichChemical Co.

ODMA—octadecyl methacrylate, C₁₈H₃₇OC(O)C(CH₃)═CH₂, available fromAldrich Chemical Co.

LA—lauryl acrylate, C₁₂H₂₅OC(O)CH═CH₂, available from Aldrich ChemicalCo.

MMA—methyl methacrylate, CH₃OC(O)C(CH₃)═CH₂, available from AldrichChemical Co.

UNICID™ 700—polyethylene 700 acid (having around 50 carbon atoms),available from Petrolite Corp., St. Louis, Miss.

EMPOL™ 1008—distilled and hydrogenated dimer acid made from oleic acid,having an acid equivalent weight of 305 as determined by titration,available from Henkel Corp./Emery Group.

dodecyl mercaptan—C₁₂H₂₅SH, available from Aldrich Chemical Co.

octadecyl mercaptan—C₁₈H₃₇SH, available from Aldrich Chemical Co.

3-mercaptopropionic acid—HSCH₂CH₂COOH, available from Aldrich ChemicalCo.

methyl 3mercaptopropionate—HSCH₂CH₂COOCH₃, available from AldrichChemical Co.

AIBN—2,2′-azobisisobutyronitrile, available as VAZO™ 64 initiator fromE. I. duPont de Nemours & Co., Wilmington, Del.

VAZO™ 88 initiator, available from E. I. duPont de Nemours & Co.

MeFOSE—C₈F₁₇SO₂N(CH₃)CH₂CH₂OH, can be prepared using the generalprocedure described in Example 3 of U.S. Pat. No. 2,803,656.

TELOMER-A—FLUOWET™ AC-812 fluoroacrylate monomer,CF₃(CF₂)_(n)CH₂CH₂OC(O)CH═CH₂, where n is a value ranging from about 3to 11 and averaging about 7, available from Hoechst Aktiengesellschaft,Frankfurt Am Main, Germany).

MeFOSEA—C₈F₁₇SO₂N(CH₃)C₂H₄OC(O)CH═CH₂, can be prepared using the generalprocedure described in U.S. Pat, No. 2,803,615.

MeFOSEMA—C₈F₁₇SO₂N(CH₃)C₂H₄OC(O)C(CH₃)═CH₂, can be prepared by thegeneral procedure described in U.S. Pat. No. 2,803,615.

MeFBSEA—C₄F₉SO₂N(CH₃)CH₂CH₂OC(O)CH═CH₂, can be prepared using thegeneral procedure described in U.S. Pat. No. 2,803,615.

MeFBSEMA—C₄F₉SO₂N(CH₃)C₂H₄OC(O)C(CH₃)═CH₂, can be prepared using thegeneral procedure described in U.S. Pat, No. 2,803,615.

FC Oxazolidinone A—a polymer melt additive prepared by reactingC₈F₁₇SO₂N(CH₃)CH(OH)CH₂Cl with stearyl isocyanate at a 1:1 molar ratiofollowed by ring closure using essentially the same procedure asdescribed in Scheme I of U.S. Pat. No. 5,025,052 (Crater et al.).

FC Oxazolidinone B—a polymer melt additive prepared by reactingC₈F₁₇SO₂N(Me)CH(OH)CH₂Cl with hexamethylene diisocyanate at a 2:1 molarratio followed by ring closure using essentially the same procedure asdescribed in Scheme I of U.S. Pat. No. 5,025,052 (Crater et al.).

(MeFOSE)₂-EMPOL™ 1008—To a 500 mL 2-necked round-bottom flask equippedwith overhead condenser, thermometer and Dean-Stark trap wrapped withheat tape was charged 57.8 g (0.190 eq) of Empol™ 1008 dimer acid, 100 g(0.185 eq) of MeFOSE, 1 g of p-toluenesulfonic acid and 50 g of toluene.The resulting mixture was placed in an oil bath heated to 150° C. Thedegree of esterification was monitored by measuring the amount of watercollected in the Dean-Stark trap and also by using gas chromatography todetermine the amount of unreacted fluorochemical alcohol. After 18 hoursof reaction, about 2.8 mL of water was collected and a negligible amountof fluorochemical alcohol remained, indicating a complete reaction. Thereaction mixture was then cooled to 100° C. and was twice washed with120 g aliquots of deionized water to a water pH of 3. The final wash wasremoved from the flask by suction, and the reaction mixture was heatedto 120° C. at an absolute pressure of about 90 torr to remove volatiles.The product, a brownish solid, was characterized as containing thedesired product by ¹H and ¹³C NMR spectroscopy and thermogravimetricanalysis.

MeFOSE-UNICID™ 700—To a 3-necked round bottom flask equipped with amechanical stirrer and Dear-Stark apparatus was added 135 g (0.242 mol)of MeFOSE, 215.7 g (0.242 mol) of UNICID™ 700, 3.5 g of methanesulfonicacid and 400 mL of toluene. The resulting mixture was heated to refluxfor approximately 15 hours, during which time water had collected in theDean-Stark apparatus. IR spectra of this mixture showed no —COOH or —OHpeaks. To this hot mixture 10 g of Ca(OH)₂ was added slowly withstirring, and the hot solution was filtered. Toluene was removed fromthe filtrate by heating under reduced pressure, and the remaining solidswere dried in a vacuum oven.

PP3505—ESCORENE™ PP3505 polypropylene, having a 400 melt index flowrate, available from Exxon Chemical Co., Baytown, Tex.

PE6806—ASPUN™ 6806 polyethylene, having a melt flow index of 105 g/10min (as measured by Test Method ASTM D-1238) and having a peak meltingpoint of 124.8° C., available from Dow Chemical Co., Midland, Mich.

PS440-200—MORTHANE™ PS440-200 urethane, available from Morton ThiokolCorp., Chicago, Ill.

PET 65-1000—polyethylene terephthalate available from the 3M Company,Decatur, Ala.

Preparation of Fluorochemical Oligomeric Compounds and Intermediates

(MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃—To a round bottom flask equipped withstirrer, thermometer, reflux condenser and nitrogen bubbler was added122.5 g (0.2 mol) of MeFOSEA monomer, 16.2 g (0.05 mol) of ODA and 150mL of ethyl acetate. While stirring, nitrogen was bubbled through theresulting solution for 15 minutes. Then to this solution was added 6.0 g(0.05 mol) of methyl 3-mercaptopropionate, and nitrogen was bubbled intothe solution for another 2 minutes. 0.5 wt % of AIBN was added and theresulting mixture was heated to 65° C. for about 15 hours under anitrogen atmosphere. IR spectra of this material showed the absenceof >C═C< peak at 1637 cm⁻¹, indicating no residual monomer. The reactionproduct was poured into a 50:50 blend of methyl alcohol and hexanes, andthe white powder which precipitated was filtered and dried for about 5-6hours at 50-60° C. under vacuum. TGA of this material showed onset ofthermal degradation in air at 346° C. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(MeFOSEA)₄(ODA)₁, higher molecular weight, made in EtOAc—This randomcopolymer was made in exactly the same way as was(MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃, except no chain transfer agent (methyl3-mercaptopropionate) was used. The resulting molecular weight was notmeasured but is believed to be considerably higher than when the chaintransfer agent was employed.

(MeFOSEA)₄(ODA)₁, higher molecular weight, made in IPA—This randomcopolymer was made in exactly the same way as was(MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃, except no chain transfer agent was usedand the polymerization solvent was isopropyl alcohol instead of ethylacetate. The resulting molecular weight was not measured but is believedto be considerably higher than when the chain transfer agent wasemployed.

(MeFOSEMA)₄(ODA)₁—SCH₂CH₂COOCH₃—This random copolymer was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃, except that the MeFOSEA was replacedwith an equimolar amount of MeFOSEMA. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(TELOMER-A)₄(ODA)₁—SCH₂CH₂COOCH₃—This random copolymer was preparedusing essentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃, except that the MeFOSEA was replacedwith an equimolar amount of TELOMER-A. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(MeFOSEA)₄(LA)₁—SCH₂CH₂COOCH₃—This random copolymer was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃, except that the ODA was replaced with anequimolar amount of LA. The calculated average number of polymerizedmonomer units per polymer chain is 5.

(MeFOSEA)₄(MMA)₁—SCH₂CH₂COOCH₃—This random copolymer was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃, except that the ODA was replaced with anequimolar amount of MMA. The calculated average number of polymerizedmonomer units per polymer chain is 5.

(MeFOSEA)₄(UNILIN™ 425A)₁—SCH₂CH₂COOCH₃—To a round bottom flask equippedwith stirrer, thermometer, reflux condenser and nitrogen bubbler wasadded 122.5 g (0.2 mol) of MeFOSEA monomer, 29.4 g (0.05 mol) of UNILIN™425A and 160 mL of methyl isobutyl ketone (MIBK). While stirring at 90°C., nitrogen was bubbled through the resulting solution for 15 minutes.Then to this solution was added 6.0 g (0.05 mol) of methyl3-mercaptopropionate, and nitrogen was bubbled into the solution foranother 2 minutes. 0.8 % (wt) of VAZO™ 88 was added and the resultingmixture was heated to 95-100° C. for about 24 hours under a nitrogenatmosphere. IR spectra of this material showed the absence of >C═C< peakat 1637 cm⁻¹, indicating no residual monomer. The MIBK was evaporatedunder reduced pressure. The calculated average number of polymerizedmonomer units per polymer chain is 5.

(MeFOSEA)₄(UNILIN™ 700A)₁—SCH₂CH₂COOCH₃—This random copolymer wasprepared using essentially the same procedure as described for preparing(MeFOSEA)₄(UNILIN™ 425A)₁—SCH₂CH₂COOCH₃, except that the UNILIN™ 425Awas replaced with an equimolar amount of UNILIN™ 700A. The calculatedaverage number of polymerized monomer units per polymer chain is 5.

(MeFBSEA)₄(UNILIN™ 700A)₁—S—CH₂CH₂COOCH₃—This random copolymer wasprepared using essentially the same procedure as described for preparing(MeFOSEA)₄ (UNILIN™ 425A)₁—SCH₂CH₂COOCH₃, except that the UNILIN™ 425Awas replaced with an equimolar amount of UNILIN™ 700A and the MeFOSEAwas replaced with an equimolar amount of MeFBSEA. The calculated averagenumber of polymerized monomer units per polymer chain is 5.

(MeFBSEMA)₄(UNILIN™ 700A)₁—SCH₂CH₂COOCH₃—This random copolymer wasprepared using essentially the same procedure as described for preparing(MeFOSEA)₄(UNILIN™ 425A)₁—SCH₂CH₂COOCH₃, except that the UNILIN™ 425Awas replaced with an equimolar amount of UNILIN™ 700A and the MeFOSEAwas replaced with an equimolar amount of MeFBSEMA. The calculatedaverage number of polymerized monomer units per polymer chain is 5.

(MeFBSEMA)₄(UNILIN™ 700A)₁, high molecular weight—This random copolymerwas prepared using essentially the same procedure as described forpreparing (MeFOSEA)₄(UNILIN™ 700A)₁—SCH₂CH₂COOCH₃, except that no chaintransfer agent (methyl 3-mercaptopropionate) was used. The resultingmolecular weight was not measured but is believed to be considerablyhigher than when the chain transfer agent was employed.

(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COOH—To a round bottom flask equipped withstirrer, thermometer, reflux condenser and nitrogen bubbler was added122.5 g (0.2 mol) of MeFOSEA, 16.2 g (0.05 mol) of ODA, and 150 mL ofethyl acetate. The contents of the flask were stirred to form asolution, and nitrogen was bubbled through the solution for 15 minutes.To this solution was then added 5.3 g (0.05 mol) of 3-mercaptopropionicacid, and nitrogen was bubbled through the contents of the flask for anadditional 2 minutes. 0.5 wt % of AIBN was added, and the resultingmixture was heated to 65° C. for approximately 15 hours under a nitrogenatmosphere. IR spectra of this material showed the absence of a >C═C<peak at 1637 cm⁻¹, indicating the absence of the monomers. The polymersolution was poured in hexanes, causing the polymer to precipitate as awhite powder, which was removed by filtration and dried at 50-60° C.under vacuum.

(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COO-UNILIN™ 700—To a 3-necked round bottomflask equipped with a mechanical stirrer and Dear-Stark apparatus wasadded 50 g (0.0174 mol) of(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COOH, 15 g (0.0174mol) of UNILIN™ 700 alcohol, 1 mL of methanesulfonic acid and 100 mL oftoluene. The resulting mixture was heated to reflux for approximately 15hours, during which time some water had collected in the Dean-Starkapparatus. IR spectra of this mixture showed no —COOH or —OH peaks. Tothis hot mixture, 5 g of Ca(OH)₂ was slowly added with stirring, and theresulting hot solution was filtered. Toluene was removed from thefiltrate by heating under reduced pressure, and the remaining solidswere dried in a vacuum oven.

(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COO-UNILIN™ 425—This ester was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COO-UNILIN™ 700, except that the UNILIN™ 700Alcohol was replaced with an equimolar amount of UNILIN™ 425 Alcohol.

(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COO—C₁₈H₃₇—This ester was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COO-UNILIN™ 700, except that the UNILIN™ 700Alcohol was replaced with an equimolar amount of stearyl alcohol.

(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COO—C₂₂H₄₅—This ester was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COO-UNILIN™ 700, except that the UNILIN™ 700Alcohol was replaced with an equimolar amount of behenyl alcohol.

(MeFOSEA)₄(ODA)₁—S—CH₂CH₂COO-MeFOSE—To a 3-necked round bottom flaskequipped with a mechanical stirrer and Dear-Stark apparatus was added 60g (0.0208 mol) of (MeFOSEA)₄(ODA)₁—S—CH₂CH₂COOH, 11.6 g (0.0208 mol) ofMeFOSE, 1 mL of methanesulfonic acid and 100 mL of toluene. Theresulting mixture was heated to reflux for approximately 15 hours,during which time some water had collected in the Dean-Stark apparatus.IR spectra of this mixture showed no —COOH or —OH peaks. To this hotmixture 5 g of Ca(OH)₂ was slowly added with stirring, and the hotsolution was filtered. Toluene was removed from the filtrate by heatingunder reduced pressure, and the remaining solids were dried in a vacuumoven.

(MeFOSEA)₄(ODA)₁—SC₁₂H₂₅—To a round bottom flask equipped with stirrer,thermometer, reflux condenser and nitrogen bubbler was added 122.5 g(0.2 mol) of MeFOSEA, 16.2 g (0.05 mol) of ODA and 150 mL of ethylacetate. While stirring, nitrogen was bubbled through the resultingsolution for 15 minutes. Then to this solution was added 10.1 g (0.05mol) of dodecyl mercaptan, and nitrogen was bubbled into the solutionfor an additional 2 minutes. 0.5 % (wt) of AIBN was added and theresulting mixture was heated to 65° C. for about 15 hours under anitrogen atmosphere. IR spectra of this material showed the absenceof >C═C< peak at 1637 cm⁻¹, indicating no residual monomer. The reactionproduct was poured into a 50:50 blend of methyl alcohol and hexanes, andthe white powder which precipitated was filtered and dried for about 5-6hours at 50-60° C. under vacuum. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(TELOMER-A)₄(ODA)₁—SC₁₂H₂₅—This random copolymer was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—SC₁₂H₂₅, except that the MeFOSEA was replaced with anequimolar amount of TELOMER-A. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(MeFOSEA)₄(ODMA)₁—SC₁₂H₂₅—This random copolymer was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₄(ODA)₁—SC₁₂H₂₅, except that the ODA was replaced with anequimolar amount of ODMA. The calculated average number of polymerizedmonomer units per polymer chain is 5.

(MeFOSEA)₃(ODA)₂—SC₁₂H₂₅—To a round bottom flask equipped with stirrer,thermometer, reflux condenser and nitrogen bubbler was added 91.7 g(0.15 mol) of MeFOSEA, 32.5 g (0.10 mol) of ODA and 150 mL of ethylacetate. While stirring, nitrogen was bubbled through the resultingsolution for 15 minutes. Then to this solution was added 10.1 g (0.05mol) of dodecyl mercaptan, and nitrogen was bubbled into the solutionfor an additional 2 minutes. 0.5% (wt) of AIBN was added and theresulting mixture was heated to 65° C. for about 15 hours under anitrogen atmosphere. IR spectra of this material showed the absenceof >C═C< peak at 1637 cm⁻¹, indicating no residual monomer. The reactionproduct was poured into a 50:50 blend of methyl alcohol and hexanes, andthe white powder which precipitated was filtered and dried for about 5-6hours at 50-60° C. under vacuum. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(MeFOSEA)_(2.5)(ODA)_(2.5)—SC₁₂H₂₅—To a round bottom flask equipped withstirrer, thermometer, reflux condenser and nitrogen bubbler was added76.4 g (0.125 mol) of MeFOSEA, 40.6 g (0.125 mol) of ODA and 150 mL ofethyl acetate. While stirring, nitrogen was bubbled through theresulting solution for 15 minutes. Then to this solution was added 10.12g (0.05 mol) of dodecyl mercaptan, and nitrogen was bubbled into thesolution for an additional 2 minutes. 0.5% (wt) of AIBN was added andthe resulting mixture was heated to 65° C. for about 15 hours under anitrogen atmosphere. IR spectra of this material showed the absenceof >C═C< peak at 1637 cm⁻¹, indicating no residual monomer. The reactionproduct was poured into a 50:50 blend of methyl alcohol and hexanes, andthe white powder which precipitated was filtered and dried for about 5-6hours at 50-60° C. under vacuum. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(MeFOSEA)₂(ODMA)₃—SC₁₂H₂₅—To a round bottom flask equipped with stirrer,thermometer, reflux condenser and nitrogen bubbler was added 40 g(0.0654 mol) of MeFOSEA, 30 g (0.0887 mol) of ODMA and 100 mL ofisopropyl alcohol. While stirring, nitrogen was bubbled through theresulting solution for 15 minutes. Then to this solution was added 5.0 g(0.0247 mol) of dodecyl mercaptan, and nitrogen was bubbled into thesolution for an additional 2 minutes. 0.5 wt % of AIBN was added and theresulting mixture was heated to 70° C. for about 10 hours under anitrogen atmosphere. IR spectra of this material showed the absenceof >C═C< peak at 1637 cm⁻¹, indicating no residual monomer. The reactionproduct was poured into a 50:50 blend of methyl alcohol and hexanes, andthe white powder which precipitated was filtered and dried for about 5-6hours at 50-60° C. under vacuum. TGA of this material showed onset ofthermal degradation in air at 346° C. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(TELOMER-A)₂(ODMA)₃—SC₁₂H₂₅—This random copolymer was prepared usingessentially the same procedure as described for preparing(MeFOSEA)₂(ODMA)₃—SC₁₂H₂₅, except that the MeFOSEA was replaced with anequimolar amount of TELOMER-A. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(MeFOSEA)₄(ODA)₁—SC₁₈H₃₇—To a round bottom flask equipped with stirrer,thermometer, reflux condenser and nitrogen bubbler was added 122.5 g(0.2 mol) of MeFOSEA, 16.2 g (0.05 mol) of ODA and 150 mL of ethylacetate. While stirring, nitrogen was bubbled through the resultingsolution for 15 minutes. Then to this solution was added 14.3 g (0.05mol) of octadecyl mercaptan, and nitrogen was bubbled into the solutionfor an additional 2 minutes. 0.5% (wt) of AIBN was added and theresulting mixture was heated to 65° C. for about 15 hours under anitrogen atmosphere. IR spectra of this material showed the absenceof >C═C< peak at 1637 cm⁻¹, indicating no residual monomer. The reactionproduct was poured into a 50:50 blend of methyl alcohol and hexanes, andthe white powder which precipitated was filtered and dried for about 5-6hours at 50-60° C. under vacuum. The calculated average number ofpolymerized monomer units per polymer chain is 5.

(MeFOSEA)₄(UNILIN™ 700A)₁—SC₁₈H₃₇—This random copolymer was preparedusing essentially the same procedure as described for preparing(MeFOSEA)₄(UNILIN425A)₁—SCH₂CH₂COOCH₃, except that the UNILIN 425A wasreplaced with an equimolar amount of UNILIN™ 700A and the HSCH₂CH₂CO₂CH₃was replaced by an equimolar amount of HSC₁₈H₃₇. The calculated averagenumber of polymerized monomer units per polymer chain is 5.

Test Methods

Melt-Blown Extrusion Procedure—The melt-blown extrusion procedure usedis the same as described in U.S. Pat. No. 5,300,357, column 10, which isherein incorporated by reference. The extruder used is a Brabender 42 mmconical twin screw extruder, with maximum extrusion temperature of270-280° C. and distance to the collector of 12 inches (30 cm).

Fluorochemical and thermoplastic polymer mixtures are mixed by blendingthe thermoplastic polymer and fluorochemical polymer melt additive (ifused) in a paperboard container using a mixer head affixed to a handdrill for about one minute until a visually homogeneous mixture isobtained.

The process condition for each mixture is the same, including the meltblowing die construction used to blow the microfiber web, the basisweight of the web (55±5 g/m²) and the diameter of the microfibers (5-18micrometers). Unless otherwise stated, the extrusion temperature (i.e.,die temperature) is 270-280° C., the primary air temperature is 270° C.,the pressure is 124 kPa (18 psi), with a 0.076 cm air gap width, and thepolymer throughput rate is about 180 g/hr/cm.

Water Repellency Test—Nonwoven web samples were evaluated for waterrepellency using 3M Water Repellency Test V for Floorcoverings (February1994), available from 3M Company. In this test, samples are challengedto penetrations by blends of deionized water and isopropyl alcohol(IPA). Each blend is assigned a rating number as shown below:

Water Repellency Water/IPA Rating Number Blend (% by volume) 0 100%water 1 90/10 water/IPA 2 80/20 water/IPA 3 70/30 water/IPA 4 60/40water/IPA 5 50/50 water/IPA 6 40/60 water/IPA 7 30/70 water/IPA 8 20/80water/IPA 9 10/90 water/IPA 10 100% IPA

In running the Water Repellency Test, a nonwoven web sample is placed ona flat, horizontal surface. Five small drops of water or a water/IPAmixture are gently placed at points at least two inches apart on thesample. If, after observing for ten seconds at a 45° angle, four of thefive drops are visible as a sphere or a hemisphere, the nonwoven websample is deemed to pass the test. The reported water repellency ratingcorresponds to the highest numbered water or water/IPA mixture for whichthe nonwoven sample passes the described test.

It is desirable to have a water repellency rating of at least 4,preferably a rating at least 6.

Oil Repellency Test—Nonwoven web samples were evaluated for oilrepellency using 3M Oil Repellency Test III (February 1994), availablefrom 3M Company, St. Paul, Minn. In this test, samples are challenged topenetration by oil or oil mixtures of varying surface tensions. Oils andoil mixtures are given a rating corresponding to the following:

Oil Repellency Oil Rating Number Composition 0 (fails Kaydol ™ mineraloil) 1 Kaydol ™ mineral oil 2 65/35 (vol) mineral oil/n-hexadecane 3n-hexadecane 4 n-tetradecane 5 n-dodecane 6 n-decane 7 n-octane 8n-heptane

The Oil Repellency Test is run in the same manner as is the WaterRepellency Test, with the reported oil repellency rating correspondingto the highest oil or oil mixture for which the nonwoven web samplepasses the test.

It is desirable to have an oil repellency rating of at least 1,preferably a rating of at least 3.

DOP Wetting Time Test—Nonwoven webs were challenged to resistance toDioctyl phthalate (DOP) by placing a small drop of neat DOP on the weband measuring the time for the drop to spread or wet the web (consideredthe time of failure). Webs which were not wet after one day wereconsidered to be resistant indefinitely to DOP.

EXAMPLES 1-9 AND COMPARATIVE EXAMPLES C1-C5

In Examples 1-9, fluorinated compounds having several variations influorinated and fluorine-free monomer in their fluorochemical oligomericportions were made and evaluated as polymer melt additives. In allcases, the molar monomer ratio of fluorinated monomer to fluorine-freemonomer was kept constant at 4:1 (i.e., to give an R_(f)/R_(h) ratio of4:1 for each fluorinated compound) and the chain-transfer agent used wasHSCH₂CH₂COOCH₃ (R═C₁) at a constant amount. Each fluorinated compoundwas melt-blended at 1% concentration with ESCORENE™ PP3505polypropylene. Melt-blown nonwoven webs were made according to theMelt-Blown Extrusion Procedure, and each of the resulting webs wasevaluated for repellency using the Water Repellency Test and the OilRepellency Test, both initially and after annealing the webs for 10minutes at 120° C. Also, the resistance time of the annealed nonwovenwebs to dioctyl phthalate was measured using the DOP Wetting Time Test.

In Examples 1-5, the fluorinated compounds were copolymers of MeFOSEAand various fluorine-free monomers having aliphatic groups (R_(h)) ofchain lengths of approximately C₅₀, C₃₂, C₁₈, C₁₂ and C₁, respectively.

In Example 6, the fluorinated compound was a copolymer of TELOMER-A andODA.

In Example 7, the fluorinated compound was a copolymer of MeFOSEMA andODA.

In Examples 8 and 9, the fluorinated compounds were copolymers ofUNILIN™ 700A and MeFBSEA and MeFBSEMA, respectively (each having anR_(f) chain length of C₄). In this case, each fluorinated compound wasmelt-blended at 2% concentration with PP3505 polypropylene.

In Comparative Examples C1 and C2, non-oligomeric fluorinated compoundshaving a high carbon number aliphatic moiety, an ester moiety-containinglinking group but non-oligomeric (i.e., single chain) fluorochemicalportion(s) were melt-blended at 1% concentration with PP3505. Melt-blownnonwoven webs were made according to the Melt-Blown Extrusion Procedure,and each web was evaluated as described in Examples 1-5. Thesenon-oligomeric fluorinated compounds are repellent ester-containingpolymer melt additives described in World Published Patent ApplicationsWO 97/22659 and WO 99/05345, respectively.

In Comparative Examples C3 and C₄, two fluorochemical oxazolidinones ofthe type described in U.S. Pat. No. 5,025,052, having non-oligomericportions but known to be effective polymer melt additives, weremelt-blended at 1% concentration with PP3505. Melt-blown nonwoven webswere made according to the Melt-Blown Extrusion Procedure, and testingof the modified PP3505 was conducted as described in Examples 1-5.

In Comparative Example C5, no polymer melt additive was incorporatedinto PP3505 prior to extruding the nonwoven web.

Results are presented in TABLE 1.

TABLE 1 DOP Fluorochemical Additive: Initial: Annealed: Wet. Ex. Name %WR OR WR OR Time 1 (MeFOSEA)₄(UNILIN ™ 1 3 0.5 10 8 >1 day700A)₁-SCH₂CH₂COOCH₃ 2 (MeFOSEA)₄(UNILIN ™ 1 3 0 10 6 >1 day425A)₁-SCH₂CH₂COOCH₃ 3 (MeFOSEA)₄(ODA)₁- 1 4 0 8.5 8 >1 daySCH₂CH₂COOCH₃ 4 (MeFOSEA)₄(LA)₁- 1 4 0 7.5 8 >1 day SCH₂CH₂COOCH₃ 5(MeFOSEA)₄(MMA)₁- 1 3 0.5 4.5 5 5 min S-CH₂CH₂COOCH₃ 6(TELOMER-A)₄(ODA)₁- 1 5 0.5 8 1.5 Immed. SCH₂CH₂COOCH₃ 7(MeFOSEMA)₄(ODA)₁- 1 3 0 7 2 Immed. SCH₂CH₂COOCH₃ 8 (MeFBSEA)₄(UNILIN ™2 4 3 6.5 5.5 1 day 700A)₁-SCH₂CH₂COOCH₃ 9 (MeFBSEMA)₄(UNILIN ™ 2 4.5 17.5 5 1 day 700A)₁-SCH₂CH₂COOCH₃ C1 MeFOSE-UNICID ™ 700 1 4.5 0 5 0 10sec. C2 (MeFOSE)₂-EMPOL ™ 1008 1 7 1 9 2 Immed. C3 FC Oxazolidinone A 19 2 9 2 >1 day C4 FC Oxazolidinone B 1 3 0 7 0 >1 day C5 No Additive — 20 2 0 Immed.

The data in TABLE 1 show that, in general for the annealed webs, thecompounds of this invention imparted good to excellent water, oil andDOP resistance to polypropylene.

EXAMPLES 10-17

In Examples 10-15, fluorochemical oligomeric compounds were made bycopolymerizing MeFOSEA with ODA using hydrocarbon chain transfer agentshaving alkyl chain lengths varying in size from C₁ to C₅₀. For thisstudy, the molar monomer ratio of MeFOSEA to ODA was kept constant at4:1 (i.e., to give an R_(f)/R_(h) ratio of 4:1 for each fluorinatedcompound). Each fluorinated compound was melt-blended at 1%concentration in ESCORENE™ PP3505 polypropylene. Melt-blown nonwovenwebs were made according to the Melt-Blown Extrusion Procedure, and theresulting webs were evaluated for repellency using the Water RepellencyTest and the Oil Repellency Test, both initially and after annealing thewebs for 10 minutes at 120° C. Also, the resistance time of the annealednonwoven webs to dioctyl phthalate was measured using the DOP WettingTime Test.

In Example 16, the chain lengths of the hydrocarbon group and thealiphatic moiety were reversed from those in Example 15 (i.e., fromR_(h)═C₁₈ and R═C₅₀ to R_(h)═C₅₀and R═C₁₈). The resulting compound wasevaluated as described in Examples 10-15.

In Example 17, a fluorinated compound was made by copolymerizing MeFOSEAwith ODA using a fluorochemical chain transfer agent. The resultingfluorinated compound was evaluated as described in Examples 10-15.

Results are presented in TABLE 2.

TABLE 2 DOP Fluorochemical Additive: Initial: Annealed: Wet. Ex. Name %WR OR WR OR Time 10* (MeFOSEA)₄(ODA)₁- 1 4 0 8.5 8 >1 day SCH₂CH₂COOCH₃11 (MeFOSEA)₄(ODA)₁- 1 5 0 8 3 5.5 SC₁₂H₂₅ hours 12 (MeFOSEA)₄(ODA)₁- 14.5 0 8 1 5.5 SC₁₈H₃₇ hours 13 (MeFOSEA)₄(ODA)₁- 1 3.5 0 8.5 8 >1 daySCH₂CH₂COO-C₂₂H₄₅ 14 (MeFOSEA)₄(ODA)₁₋ 1 3.5 0 10 7 >1 day SCH₂CH₂COO-UNILIN ™ 425 15 (MeFOSEA)₄(ODA)₁₋ 1 3.5 0 10 7 >1 SCH₂CH₂COO- dayUNILIN ™ 700 16 (MeFOSEA)₄(UNILIN ™ 1 3 0.5 10 8 >1 day 700A)₁-SC₁₈H₃₇17 (MeFOSEA)₄(ODA)₁- 1 3 0 9 2.5 2 SCH₂CH₂COO-MeFOSE min *Data takenfrom Example 3

The data from Examples 10-15 show that, for annealed webs, waterrepellency and resistance to wetting by DOP generally increased withincreasing chain length of the alkyl group in the aliphatic moiety (R).The oil repellency and DOP resistance after annealing was greatest atthe longest aliphatic moiety chain lengths (C₅₀, C₃₂ and C₂₂), droppingat intermediate chain lengths (C₁₈ and C₁₂), and increasing again at theshortest chain length (C₁).

The overall repellent performance imparted by the fluorochemicaloligomeric compounds in Example 13-15, where R varied from a C₂₂ to aC₅₀ alkyl group, was surprising, exceeding the performance when R was afluoroalkyl group (Example 17). The same excellent performance was alsonoted when R_(h) was the C₅₀ alkyl group (Example 16). Such oilrepellency performance is unexpected from compounds containing suchlarge oleophilic groups.

EXAMPLES 18-20 AND COMPARATIVE EXAMPLES C6-C9

In Examples 18-20 and Comparative Examples C6-C9, fluorinated compoundswere made having a varying molar ratio of fluoroaliphatic/hydrocarbonpendent groups (R_(f)/R_(h) ) in the fluorochemical oligomeric portion(A) of the fluorinated compound, keeping the chain length of thealiphatic moiety (R) constant at C₁₂. Each fluorinated compound wasmelt-blended at 1% concentration in ESCORENE™ PP3505 polypropylene.Melt-blown nonwoven webs were made according to the Melt-Blown ExtrusionProcedure, and the resulting webs were evaluated for repellency usingthe Water Repellency Test and the Oil Repellency Test, both initiallyand after annealing the webs for 10 minutes at 120° C. Also, theresistance time of the annealed nonwoven webs to dioctyl phthalate wasmeasured using the DOP Wetting Time Test.

In Example 18, the fluorochemical monomer was MeFOSEA, the fluorine-freemonomer was ODA, and the molar ratio of R_(f)/R_(h) in the fluorinatedcompound was 4/1.

In Example 19, the fluorochemical monomer was MeFOSEA, the fluorine-freemonomer was ODMA, and the molar ratio of R_(f)/R_(h) in the fluorinatedcompound was 4/1.

In Example 20, the fluorochemical monomer was TELOMER-A, thefluorine-free monomer was ODA, and the molar ratio of R_(f)/R_(h) in thefluorinated compound was 4/1.

In Comparative Examples C6 and C7, the fluorochemical monomer wasMeFOSEA, the fluorine-free monomer was ODA, and the molar ratio ofR_(f)/R_(h) in the fluorinated compounds was 3/2 and 2.5/2.5,respectively.

In Comparative Examples C8 and C9, the fluorinated compounds were of thetype described in Reference Example 6 of International PublishedApplication WO 98/15598, each having an R_(f)/R_(h) molar ratio of lessthan 1/1.

Results are presented in TABLE 3.

TABLE 3 DOP Fluorochemical Additive: Initial: Annealed: Wet. Ex. Name %WR OR WR OR Time 18* (MeFOSEA)₄(ODA)₁- 1 5 0 8 3 5.5 SC₁₂H₂₅ hours 19(MeFOSEA)₄(ODMA)₁- 1 4 0 8 3 5.5 SC₁₂H₂₅ hours 20 (TELOMER-A)₄(ODA)₁- 16.5 0 9 0 immed. SC₁₂H₂₅ C6 (MeFOSEA)₃(ODA)₂- 1 4.5 0 8 1 2 SC₁₂H₂₅hours C7 (MeFOSEA)_(2.5)(ODA)_(2.5)- 1 5 0 8 1 2 SC₁₂H₂₅ hours C8(MeFOSEA)₂(ODMA)₃- 1 4.5 0 8 1 immed. SC₁₂H₂₅ C9 (TELOMER-A)₂- 1 4.5 0 80 immed. (ODMA)₃-SC₁₂H₂₅ *Data taken from Example 11

The data in TABLE 3 show that, for the annealed webs, the oil repellencyand the resistance to wetting by DOP both improved markedly when ahigher ratio of fluoroaliphatic/hydrocarbon pendent groups (R_(f)/R_(h))was employed in the fluorochemical oligomeric portion (A) of thefluorinated compound.

COMPARATIVE EXAMPLES C10-C11 AND EXAMPLE3

In Comparative Examples C10-C11, fluorochemical polymeric compounds ofvarying molecular weights were made by copolymerizing MeFOSEA and ODA atan R_(f)/R_(h) molar ratio of 4/1 in ethyl acetate and isopropylalcohol, respectively. Each fluorinated compound was then melt-blendedat 1% concentration in ESCORENE™ PP3505 polypropylene. Melt-blownnonwoven webs were made according to the Melt-Blown Extrusion Procedure,and the resulting webs were evaluated for repellency using the WaterRepellency Test and the Oil Repellency Test, both initially and afterannealing the webs for 10 minutes at 120° C.

For comparison, Example 3 from TABLE 1, a fluorochemical oligomericcompound made by copolymerizing the monomers at the same 4/1 molar ratiobut incorporating HSCH₂CH₂COOCH₃ as a chain transfer agent, was alsoincluded. This lower molecular weight fluorinated compound was alsomelt-blended at 1% concentration and evaluated using the same testprocedures.

Results are presented in TABLE 4.

TABLE 4 Initial: Annealed: DOP Wet. Ex. Chain Transfer Agent WR OR WR ORTime C10 ethyl acetate 3 0 4 0 immed. C11 isopropyl alcohol 3 0 4 0immed. 3 HSCH₂CH₂COOCH₃ 4 0 8.5 8 10 min.

The data in TABLE 4 show that overall performance of the annealed webswas superior employing lower molecular weight fluorochemical oligomericcompounds made with the chain transfer agent as compared to thefluorochemical polymeric compounds.

COMPARATIVE EXAMPLE C12 AND EXAMPLE 9

In Comparative Example C12, a fluorochemical polymeric compound of highmolecular weight was made by copolymerizing MeFBSEMA and UNILIN™ 700A atan R_(f)/_(h) molar ratio of 4/1 in MIBK as a solvent. The resultingfluorinated compound was melt-blended at 2% concentration in ESCORENE™PP3505 polypropylene. A melt-blown nonwoven web was made according tothe Melt-Blown Extrusion Procedure, and the resulting web was evaluatedfor repellency using the Water Repellency Test and the Oil RepellencyTest, both initially and after annealing the web for 10 minutes at 120°C.

Results, presented in TABLE 5, show performance as a function of themolecular weight of the fluorinated compound. For comparison, Example 9from TABLE 1, a fluorochemical oligomeric compound made bycopolymerizing the monomers at the same 4/1 molar ratio butincorporating HSCH₂CH₂COOCH₃ as a chain transfer agent, was alsoincluded. This lower molecular weight fluorochemical oligomeric compoundwas also melt-blended at 2% concentration and evaluated using the sametest procedures.

TABLE 5 Initial: Annealed: DOP Wet. Ex. Chain Transfer Agent WR OR WR ORTime C12 MIBK 2.5 0 3 0.5 Immed. 9 HSCH₂CH₂COOCH₃ 4.5 1 7.5 5 1 day

As in TABLE 4, the data in TABLE 5 show that overall performance issuperior employing the lower molecular weight fluorochemical oligomericcompound.

EXAMPLE 21 AND COMPARATIVE EXAMPLE C13

In Example 21, (MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃ was melt-blended at 1%concentration with MORTHANE™ PS440-200 polyurethane. A melt-blownnonwoven web was made according to the Melt-Blown Extrusion Procedure,using an air temperature of 230° C. and an air temperature of 230° C.The resulting web was evaluated for repellency using the WaterRepellency Test and the Oil Repellency Test, both initially and afterannealing the web for 10 minutes at 120° C.

In Comparative Example C13, no polymer melt additive was added to thepolyurethane prior to extruding the nonwoven web.

Results are presented in TABLE 6.

TABLE 6 Fluorochemical Additive: Initial: Annealed: DOP Wet. Ex. Name %WR OR WR OR Time 21 (MeFOSBA)₄(ODA)₁- 1 5.5 8 7 8 20 min. SCH₂CH₂COOCH₃C13 — 1 1 0 2 0.5 Immed.

The data in TABLE 6 show that the fluorochemical oligomeric compound,when used as a polymer melt additive, greatly enhanced the water, oiland DOP repellency of the polyurethane, both initially and afterannealing.

EXAMPLE 22 AND COMPARATIVE EXAMPLE C14

In Example 22, (MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃ was melt-blended at 1%concentration with ASPUN™ 6806 polyethylene. A melt-blown nonwoven webwas made according to the Melt-Blown Extrusion Procedure, using anextrusion temperature of 240° C. and an air temperature of 236° C. Theresulting web was evaluated for repellency using the Water RepellencyTest and the Oil Repellency Test, both initially and after annealing theweb for 10 minutes at 120° C.

In Comparative Example C14, no polymer melt additive was added to thepolyurethane prior to extruding the nonwoven web.

Results are presented in TABLE 7.

TABLE 7 DOP Fluorochemical Additive: Initial: Annealed: Wet. Ex. Name %WR OR WR OR Time 22 (MeFOSEA)₄(ODA)₁- 1 4 0 10 8 >1 day SCH₂CH₂COOCH₃C14 — 1 3 0  6 0 immed.

The data in TABLE 7 show that the polymer melt additive greatly enhancedthe water, oil and DOP repellency of the polyethylene after annealing.

EXAMPLE 23 AND COMPARATIVE EXAMPLE C15

In Example 23, (MeFOSEA)₄(ODA)₁—SCH₂CH₂COOCH₃ was melt-blended at 1%concentration with PET 65-1000 polyester. A melt-blown nonwoven web wasmade according to the Melt-Blown Extrusion Procedure, using an extrusiontemperature of 280° C. and an air temperature of 280° C. The resultingweb was evaluated for repellency using the Water Repellency Test and theOil Repellency Test, both initially and after annealing the web for 10minutes at 120° C.

In Comparative Example C15, no polymer melt additive was added to thepolyurethane prior to extruding the nonwoven web.

Results are presented in TABLE 8.

TABLE 8 Fluorochemical Additive: Initial: Annealed: Ex. Name % WR OR WROR 23 (MeFOSEA)₄(ODA)₁- 1 3 0 5 4.5 SCH₂CH₂COOCH₃ C15 — 1 0 0 0 0

The data in TABLE 8 show that the polymer melt additive greatly enhancedthe water and oil repellency of the polyester after annealing.

EXAMPLE 24 AND COMPARATIVE EXAMPLE C16

Molded castings were made from a two-part, room temperature-curable,thermoset epoxy resin system (3M SCOTCH-WELD™ 1838 B/A Epoxy AdhesiveTube Kit) with and without (MeFOSEA)₄(ODA)₁S—CH₂CH₂COOCH₃. After curing,the castings were evaluated for water and oil repellency.

In Example 24, 4.9 g of Part A, 4.9 g of Part B and 0.20 g of(MeFOSEA)₄(ODA)₁S—CH₂CH₂COOCH₃ were mixed together in an approximately60 mm diameter aluminum weighing pan. The sample was cured for 1 hour at120° C. and was left overnight at room temperature. The Water RepellencyTest and the Oil Repellency Test were then run on the surface of thecured casting; the same test liquids and rating scale were used as withthe nonwoven web repellency test, with the reported value correspondingto the highest number test liquid for which a drop, when placed on thesurface of the film, would not spread.

In Comparative Example C16, the same epoxy resin preparation andevaluation was run as described in Example 23, except that the(MeFOSEA)₄(ODA)₁S—CH₂CH₂COOCH₃ was omitted.

Results are presented in TABLE 9.

TABLE 9 Composition Water Oil Ex. of Epoxy Casting Repellency Repellency24 1838 + 2% FC 6 2 C16 1838 only 0.5 0.5

The data in TABLE 9 show that the casting made from epoxy resin having(MeFOSEA)₄(ODA)₁S—CH₂CH₂COOCH₃ added thereto exhibited dramaticallyimproved water and oil repellency relative to the casting made fromepoxy resin only.

EXAMPLES 25-26 AND COMPARATIVE EXAMPLES C17-C18

Molded castings were made from a one-part, moisture-curable, thermosetpolyurethane resin system (found in 3M EC-5200 Marine Adhesive Sealant)with and without (MeFOSEA)₄(ODA)₁S—CH₂CH₂COOCH₃. After curing, thecastings were evaluated for water and oil repellency.

For each example, 4.9 g of EC-5200 sealant and 0.1 gof(MeFOSEA)₄(ODA)₁S—CH₂CH₂COOCH₃ were mixed together in twoapproximately 60 mm diameter aluminum weighing pans, and the mixture wasstirred. For Example 25, the resin system in the first pan was allowedto cure for 63 hours under ambient conditions (approximately 50%relative humidity). For Example 26, the resin system in the second panwas baked for 72 hours at 50° C. The Water Repellency Test and the OilRepellency Test were then run on the surface of each cured resin; thesame test liquids and rating scale were used as with the nonwoven webrepellency test, with the reported value corresponding to the highestnumber test liquid for which a drop, when placed on the surface of thefilm, would not spread.

In Comparative Examples C17-C18, the same moisture-cured polyurethaneresin preparation and evaluation was run as described in Examples 25-26,respectively, except that (MeFOSEA)₄(ODA)₁S—CH₂CH₂COOCH₃ was omitted ineach case.

Results are presented in TABLE 10.

TABLE 10 Composition Ambient Water Oil Ex. of Urethane Casting or BakeRepellency Repellency 25 5200 + 2.0% FC Ambient 5 1.5 C17 5200 onlyAmbient 3 0 26 5200 + 2.0% FC Bake 10 10 C18 5200 only Bake 3.5 0

The data in TABLE 10 show that castings made from moisture-curedpolyurethane resin having (MeFOSEA)₄(ODA)₁S—CH₂CH₂COOCH₃ added theretoexhibited dramatically improved water and oil repellency to castingsmade from moisture-cured polyurethane resin only, cured either underambient conditions or baked.

We claim:
 1. polymer composition comprising a thermoplastic or thermosetpolymer and at least one fluorochemical oligomeric compound comprising:(iv) an oligomeric portion having both fluoroaliphatic and fluorine-freealiphatic pendent groups; (v) an aliphatic moiety; and (vi) a linkinggroup which links the oligomeric portion to the aliphatic moiety,wherein the ratio of fluoroaliphatic pendent groups to fluorine-freealiphatic pendent groups is greater than or equal to
 4. 2. Thecomposition of claim 1 wherein said oligomeric compound is selected fromthe group consisting of [(A)_(m)—L]_(n)R and (A)_(m)[L—R]_(n) wherein mis 1 or 2; n is 1 to 4 inclusive; each L independently comprises anon-polymeric linking group; each R is a saturated or unsaturatedaliphatic moiety; and each A is a fluorochemical oligomeric portion ofFormula III: wherein the sum of a+b is an number such that A isoligomeric and comprises a plurality of pendent R_(f) and R_(h) groupsin a ratio of ≧4; each R₁ is hydrogen, halogen, or straight chain orbranched chain alkyl containing 1 to about 4 carbon atoms; each R₂ isindependently hydrogen or straight chain or branched chain alkylcontaining 1 to about 4 carbon atoms; Q and Q′ are each independently acovalent bond or an organic linking group, R_(f) is a fluoroaliphaticgroup, such as —(CF₂)₇CF₃, that comprises a fully fluorinated terminalgroup; R_(h) is a fluorine-free aliphatic group; and X is a hydrogenatom or a group derived from a free radical initiator.
 3. The compoundsof claim 2 wherein Rf has the structure C_(o)F_(2o+1), where o is 4 to14.
 4. The compounds of claim 2 wherein L is selected from the group ofa covalent bond, straight chain, branched chain, or cyclic alkylene,arylene, aralkylene, oxy, oxo, hydroxy, thio, sulfonyl, sulfoxy, amino,imino, sulfonamido, carboxamido, carbonyloxy, urethanylene, ureylene,and combinations thereof.
 5. The compounds of claim 2 wherein L ischosen from the group consisting of a covalent bond, —(CH₂)_(k)O(O)C——CH₂CH(OR₂′)CH₂C(O)O— —(CH₂)_(k)C(O)O— —(CH₂)_(k)O——(CH₂)_(k)O(CH₂)_(k)O(O)C— and —(CH₂)_(k)OCONH—

wherein each k is independently an integer from 0 to about 20, and R₂′is alkyl of 1 to about 20 carbon atoms.
 6. The compounds of claim 2comprising oligomerized units of compounds of the formula

wherein R₁, R₂, R_(f), R_(h) and Q are as defined in claim
 2. 7. Thecomposition of claim 1 wherein said thermoplastic polymers are selectedfrom the group consisting of polyamides, polyesters, polyurethanes,acrylates and polyolefins.
 8. The composition of claim 1 wherein saidfluorinated oligomeric compound comprises from 0.5 to 5 weight percentof said composition.
 9. A shaped article comprising the composition ofclaim
 1. 10. The shaped article of claim 9 wherein said fluorinatedoligomeric compound comprises from 10 to 10,000 ppm fluorine.
 11. Theshaped article of claim 9 selected from the group of films, sheets andfibers.
 12. An oily mist resistant electret filter medium comprisingpolypropylene electret fibers comprising the composition of claim
 1. 13.The filter medium of claim 12 wherein said fibers have an effectivefiber diameter of 2 to 30 micrometers.
 14. The filter medium of claim 13wherein said fibers have been annealed.
 15. The filter medium of claim13 wherein said filter media has a basis weight of 10 to 100 g/m². 16.The composition of claim 2 wherein R_(h) is a linear or branched alkylgroup having from 18 to 60 carbon atoms.
 17. A fabric comprising thefibers of claim
 11. 18. A medical gown comprising the fabric of claim17.
 19. The composition of claim 1 wherein said thermoset polymer isselected from polyurethanes, epoxy resins, epoxides and acrylates.